Two thirds of the world’s dolmens are contained in the Korean peninsula. The Gochang, Hwaun, and Ganghwa dolmen sites can be found on the UNESCO World Heritage list. This probably begs the question, from me at least – what are dolmens exactly? They are stone monuments, generally consisting of two supporting stones and a cover stone (see picture). Some are confirmed to have been tombs. Many of the cover stones are turtle-shaped, and the turtle was a symbol of longevity, both in this life and the afterlife.
Although no written records remain that describe the purpose of the dolmen stones, we can tell that they date back to the Old Choseon period (23rd – 2nd century BC). We can also measure their weight. Astonishingly, the cover stone by itself can be as heavy as 102 tons.
One particularly interesting fact about dolmen stones, however, has recently come to light. A number of the stones, concentrated in Pyongyang, had decorative markings, and their precise meaning for a long time had remained a mystery. As they were clearly intentional markings, people assumed that they were perhaps funereal symbols.
Pyongyang happens to be an ideal location for observing the stars, and it was in time realised that the marks on the stones were astronomical depictions. This ran contrary to the belief that the world’s earliest astronomical markings were those of the Babylonian boundary stones of Mesopotamia (~1200 BC), known as one of the four cradles of civilisation. Dolmen stones in the Taedong River (~3000 BC) precede the Babylonian stones by a considerable margin.
It was also realised that the size of the holes depended on the brightness of the star, and that successive generations of Old Choseon astronomers improved the accuracy of their techniques. There is a clear difference in precision between the stones discovered in the South Pyongan area (2800 BC) and the South Hamgyong dolmens (1500 BC), for instance.
Korean beliefs about the afterlife in ancient times were likely linked to worship of the heavens, so it is no coincidence that these depictions appeared on tombs.
Like most Korean achievements, these pioneering feats in astronomy, made long before the time of telescopes, were hard to uncover and, once uncovered, difficult to believe.